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470 TROPICAL NATUREearth thus attached to birds' feet several plants were raised.As showing the importance of this mode of transport, anexperiment was made with six and three -fourths ounces ofmud taken from the edge of a little pond, and it was foundto contain the enormous number of five hundred and thirtysevenseeds of several distinct species! This was proved bykeeping the mud under glass and pulling up each plant as itappeared, and at the end of six months the result was asgiven above. It was also found that small portions of aquaticplants were often entangled in the feet of birds, and to theseas well as to the feet themselves, molluscs or their eggs werefound to be attached, furnishing a mode of distribution forsuch organisms. Experiments were also made on the powerof land-shells to resist the action of sea-water ;and we havealready referred to the observations on volcanic dust carriedfar out to sea, illustrating the facilities for the wide extensionby aerial currents of such plants as have very minute or verylight seeds. l The facts are of so anomalous and apparentlycontradictory a character that, on the old hypothesis of thespecial independent creation of each species, no rationalexplanation of them could be found ;and we may fairlyclaim that the clear and often detailed explanation which canbe given by means of the theories and investigations ofDarwin, lend a powerful support to his views, and go far tocomplete the demonstration of their correctness.Our space will not permit us to do more than advert tothe numerous ingenious explanations and suggestions withwhich the Origin of Species abounds, such as, for example, thestrange fact of so many of the beetles of Madeira being wingless,while the same species, or their near allies on the continentof Europe, have full powers of flight ;and that this isnot due to any direct action of climate or physical conditionsis proved by the equally curious fact that such species ofinsects as have wings in Maderia, have them rather largerthan usual. Equally new and important is the Darwinianexplanation of the form of the bees' cell, which is shown toi This series of observations and experiments, supplemented by those ofother observers, have been applied by the writer of this article to explainsome indetail the remarkable phenomena presented by the distribution ofanimals and plants over the chief islands of the glooe. See Island Life.Macmillan and Co.